US President Donald Trump has hailed an overnight military strike on Syria as "perfectly executed", adding "Mission Accomplished".
The US, UK and France bombed three government sites, targeting what they said were chemical weapons facilities.
The strikes were in response to a suspected deadly chemical attack on the town of Douma last week.
Russian President Vladimir Putin said he condemned the Western strikes "in the most serious way".
Russia, Syria's main ally, had threatened military retaliation if any Russian forces had been hit.
In early morning tweets from Washington, President Trump thanked France and the UK for "their wisdom and the power of their fine military".
He added: "So proud of our great military", saying that after extra funding it would be "the finest our country has ever had".
In a Friday evening address to the nation from the White House, he had said: "The nations of Britain, France, and the United States of America have marshalled their righteous power against barbarism and brutality.
"The purpose of our actions tonight is to establish a strong deterrent against the production, spread, and use of chemical weapons."
The wave of strikes is the most significant attack against President Bashar al-Assad's government by Western powers in seven years of Syria's civil war.